When does the lac-operon in E.coli become "switched on"
A
Lactose is present and it binds to the repressor
B
Lactose is present and it binds to RNA polymerase
C
RNA polymerase binds to operator
D
Repressor binds to operator
Correct option is C. Lactose is present and it binds to the repressor
Lactose is inducer. It binds to repressor protein and operon is switched on.
So, the correct answer is 'Lactose is present and it binds to the repressor'